1. Field of the Invention
The present invention relates to a focus detection apparatus capable of detecting focal points for all objects with accuracy to some extent.
2. Description of the Related Art
In most of cameras having conventional focus detection apparatuses, an object area to be focused is fixed to almost the center of the viewfinder, and framing cannot be designed freely. In order to solve this problem, Japanese Patent Disclosure No. 54-59964 discloses a means capable of arbitrarily changing an angle of direction of distance measurement, wherein an operation for changing the direction of distance measurement is synchronized with a displacement of a display member for displaying the direction of distance measurement. Japanese Patent Disclosure Nos. 59-107685 and 60-254968 disclose techniques for arbitrarily selecting a sampling interval of a brightness signal to focus on any object.
A cumbersome operation for selecting a focus area is required in these prior arts and is not suitable for high-speed photographing for a moving object. A mechanical focus detection technique results in a complicated mechanism and degradation of accuracy due to the mechanism.